What happened
On December 11, 2020, a Tecnam P2006T, registration SP-MEL, was conducting an IFR training flight at Łódź Airport (EPLL). Following a touch-and-go maneuver on runway 07, the aircraft reached an altitude of approximately 1,000 ft AMSL when vibrations began occurring in the right engine. Despite reducing power, the vibrations persisted. In response, the instructor decided to shut down the engine and notified Air Traffic Control of the intention to land on runway 25. The landing was completed without further incident.
The investigation
Following the event, technical personnel inspected the engine but found no mechanical irregularities. A full engine test was conducted, which demonstrated normal operation across the entire power range. The investigation then focused on meteorological conditions. Analysis of the weather data revealed that the ambient temperature and dew point were both 0°C, with 100% humidity. These conditions were highly conducive to significant carburetor icing. The investigation noted that the observed engine vibrations are characteristic symptoms of the icing process.
Findings
- The primary cause of the incident was carburetor icing.
- Meteorological conditions, specifically the 0°C temperature and dew point combined with high humidity, facilitated the formation of ice.
- The pilot failed to recognize the symptoms of icing and incorrectly assumed a mechanical engine failure had occurred.
- The pilot did not utilize the carburetor heat as a corrective measure during the onset of the vibrations.
Safety action
- The instructor participated in a review of the event to emphasize the necessity of using carburetor heat as a primary corrective action before deciding to shut down the engine when flying in icing-prone conditions.